import java.util.Scanner;
    public class Main {
    public static void main(String[] args) {
        System.out.println("请输入电脑的价格：");
        Scanner sc = new Scanner(System.in);
        int jine = sc.nextInt();


        int day =0;
        int a=1;
        while (a<=jine){
            a=a+day+1;
            day++;
        }


            System.out.println(day);
    }
}